Extremely slow command response with mks.api Java and Windows cmd

Hi. 

I am using the com.mks.api Java library to get data from Windchill. But even when I try to run the command with windows command line, it takes minutes to get response from a simple command excecution. 

I tried the viewissue and issues commands. Also, I tried to use small Data from Windchill to rule out the too-big-data-problem. 

Also, I tried to use the method

executeWithInterim(cmd, false)

 instead of execute(), it does not help.

I also tried to use the same session for multiple commands. 

I do get an error but not sure whether it has something to do with slow response: 

Error occurred when running command: null
com.mks.api.response.CommandAlreadyRunningException
	at com.mks.connect.CmdRunnerCreatorImpl.release(CmdRunnerCreatorImpl.java:143)
	at com.mks.connect.UserApplicationSessionImpl.release(UserApplicationSessionImpl.java:494)
	at com.mks.connect.UserApplicationSessionImpl.release(UserApplicationSessionImpl.java:475)
	at com.mks.connect.UserApplicationSessionImpl.release(UserApplicationSessionImpl.java:464)
	at com.mks.connect.CmdRunnerCreatorImpl.release(CmdRunnerCreatorImpl.java:131)

Here is what the About menu shows:

Windchill RV&S 12.5.0.0

Build: 6160 

API Version: 4.16.6160

What can I do to get fast response from command exceutions?